(1) According to the meaning of the question: a=6÷0. 12×0.28= 14, B =1-(0.12+0.28+0.32+. So the answer is:14; 0.08; 4; (2) The histogram and line chart of frequency distribution are as shown in the figure. (3) According to the meaning of the question: 1000×(4÷50)=80 (people), you estimate that about 80 students in the school will enter the finals.